Please, help me center my drop-down menu

Hi guys!
I have some basic site, consisting of css divs. In one of the divs I have placed a drop-down menu. I want it to stay always at the center of the screen.
All the options that I tried did not work - it either pushes down the other divs, at drop down, or is not horizontal, or messes up in another way.
The only option that worked is fixing it to stay 350px from the left - which is not an option - as in different screen resolutions it will stay at different places. And I need it at the center.
So can you please help me with it?
All advices and ideas on fixing it are welcome as I have ran out of options already
Best regards,
Pi2a

One option that you could try is putting it into a <Tr> and positioning the DIV in the center of that, if margin-left and margin-right aren't working or are obstructing your other elements. Your wall of text kind of blanked me out, if you would be more descriptive about which element you cent centered and such then it would probably be easier for you to get help.
Best of luck.

Hi Hostwinds_Alex,
Thank you for your reply and your effort!
I will try what you suggested!
Sorry for the wall of text, I wasn't sure what I could cut off. Tried to post the .css and .htm file, but I'm not allowed, so it was blocked and I copied & pasted it.
The part I want to put in the center is the drop down menu - dd_menu part
Thank you for your time and advice!

I took a look at your CSS, what could very likely be the problem is your float: left; attribute. This could be preventing it from centering.
Disregard my previous suggestion, try taking that out and using margin-left: auto; and
margin-right: auto;

If that doesn't work, then try messing with your width attribute and see how that helps.

I took a look at your CSS, what could very likely be the problem is your float: left; attribute. This could be preventing it from centering.
Disregard my previous suggestion, try taking that out and using margin-left: auto; and
margin-right: auto;

If that doesn't work, then try messing with your width attribute and see how that helps.

If I mess with the width of the drop-down menu - I need fixed width - which bothers me because as I am not sure how wide it would be on different screens, as the drop-down menu contains text (not fixed width) and changing the text size would change the position, right?